Hivassociated Multicentric Castlemans Disease

Benjamin Castleman first described multicentric Castleman's disease (MCD) as a case record of the Massachusetts General Hospital, familiar to all the readers of the New England Journal of Medicine, in 1954.110 Interest in MCD has grown in recent years with the AIDS epidemic, since there has been an increased incidence of MCD in HIV-positive patients. This followed the recognition of an association between MCD and AIDS-associated KS, again following initial publication of case reports.4 5 Castleman's disease is divided into localized disease and MCD which is characterized by polylymphadenopathy and multiorgan involvement. The localized form is treated with surgery but the management of MCD is less clear and has a more aggressive course. Histologically, it is divided into the hyalinized vascular form and plasma variant, the former being more common in localized disease and the latter more common in MCD. MCD is associated with Kaposi's sarcoma herpesvirus (KSHV) infection, which is also known as human herpesvirus 8 (HHV-8). The virus encodes a homolog of inter-leukin 6 (IL-6), a proinflammatory cytokine, which is thought to mediate some of the clinical features of MCD. The diagnosis is established by biopsy and treatment is often based on case reports in the literature, as there are no randomized trials. Surgery has less of a role but splenectomy may be useful as a debulking procedure to alleviate hematologic sequelae. Systemic treatments have included chemotherapy as well as anti-herpesvirus treatment to reduce the KSHV viral load, and HAART to reduce HIV viral burden. Lately, treatment with monoclonal antibodies against both IL-6 and CD20 has been studied. The introduction of HAART has altered the natural history of HIV infection; however, its impact on MCD is difficult to ascertain.

The plasma cell variant of MCD occurs most frequently in people with HIV infection. The histologic appearances are of an intense plasmacytosis in the interfollicular areas of the nodes, with a prominent increase in capillaries and postcapillary venules, which may be hyalinized. The concentrically arranged mantle zone may produce a characteristic 'onion peel' appearance. KSHV has been demonstrated in nearly all MCD samples from HIV-positive patients and in half MCD patients without HIV infection.111 KSHV is also present in the malignant cells of plasmablastic lymphomas that occur more frequently in patients with MCD.112,113

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